Surface finish produced on three resin composites by new polishing systems

This study evaluated the surface finish of three direct resin composites polished with three different systems. Disk-shaped specimens (n=16 per material; phi=8.0 mm x h=2.0 mm) were formed in a stainless steel mold by packing uncured material, either a hybrid composite (Z250, 3M ESPE) or two micro-hybrid composites (Point 4, Kerr; Esthet-X, Dentsply), and light-cured from the top and the bottom surfaces with a light-emitting diode (LED) curing unit (NRG, Dentsply). After storing the specimens in deionized water at 37 degrees C for seven days, one side of each specimen was finished through 1200-grit SiC abrasive (Buehler). Five specimens of each resin composite were randomly assigned to one of the three polishing systems (Identoflex, Kerr; Pogo, Dentsply; Sof-Lex, 3M ESPE). Manufacturers' instructions were followed during the polishing procedures. The average surface roughness (Ra) was determined by generating tracings across the polished surface of each disk using a scanning profilometer (Surfanalyzer System 5000, Federal Products Co). The results were analyzed by Kruskal-Wallis and Mann and Whitney tests (p < or = 0.05). The smoothest surfaces were produced with the celluloid strip (control group) on all the resin composites tested. The aluminum oxide disks (Sof-Lex) produced a statistically equivalent surface finish (Ra) on the three resin composites. The lowest mean roughness values were recorded with diamond micropolisher disks (PoGo) on the hybrid composite (Z250). Overall, the two new polishing systems, Identoflex and PoGo, created a comparable surface finish to that produced by the Sof-Lex system on all three resin composites.